Ischemia is a condition where the flow of oxygen-rich blood to a part of the body is restricted. Cardiac ischemia refers to lack of blood flow and oxygen to the heart muscle.

Cardiac ischemia happens when an artery becomes narrowed or blocked for a short time, preventing oxygen-rich blood from reaching the heart. If ischemia is severe or lasts too long, it can cause a heart attack (myocardial infarction) and can lead to heart tissue death. In most cases, a temporary blood shortage to the heart causes the pain of angina pectoris. But in other cases, there is no pain. These cases are called silent ischemia.

The American Heart Association estimates that 3 to 4 million Americans have episodes of silent ischemia. People who have had previous heart attacks or those who have diabetes are especially at risk for developing silent ischemia. Heart muscle disease (cardiomyopathy) caused by silent ischemia is among the more common causes of heart failure in the United States.

The goals of treatment include improving blood flow to your heart and reducing your heart's need for oxygen. Your doctor may give you aspirin, anticoagulants, or other blood-thinning agents to prevent blood clots from forming. Oxygen may be given to increase the oxygen content of the blood still flowing through your heart. Painkillers may be used for pain.

Some patients take medicines that slow their heart rate, open and relax their blood vessels, and otherwise reduce the burden on the heart. Most patients respond well to these medicines. Those who do not respond well may need a percutaneous coronary intervention (PCI) such as balloon angioplasty, coronary artery bypass surgery, or a similar procedure.